Cost-utility of Intravenous Immunoglobulin (IVIG) compared with corticosteroids for the treatment of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) in Canada

A markov model was used to evaluate the costs and QALYs for IVIG and corticosteroids over 5 years of treatment for CIDP. Patients initially responding to IVIG could remain a responder or relapse every 12 week model cycle. Non-responding IVIG patients were assumed to be switched to corticosteroids. Patients on corticosteroids were at risk of a number of adverse events (fracture, diabetes, glaucoma, cataract, serious infection) in each cycle.Over the 5 year time horizon, the model estimated the incremental costs and QALYs of IVIG treatment compared to corticosteroid treatment to be $124,065 and 0.177 respectively. The incremental cost per QALY gained of IVIG was estimated to be $687,287. The cost per QALY of IVIG was sensitive to the assumptions regarding frequency and dosing of maintenance IVIG.Based on common willingness to pay thresholds, IVIG would not be perceived as a cost effective treatment for CIDP.Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immune-mediated inflammatory disorder that targets the myelin sheaths that wrap the nerves of the peripheral nervous system. The motor weakness symptoms of CIDP resemble those of Guillain-Barre syndrome (GBS), and CIDP is sometimes considered to be a chronic counterpart of GBS[1]. The course of CIDP may be chronic progressive, stepwise, or monophasic. CIDP can occur at all ages and in both sexes, but is more common in older individuals and males. It is believed that the older age group is more likely to have a chronic progressive course of CIDP, and in younger patients, a relapse remitting course[2]. The prevalence rate of CIDP has been reported to be between 1.0 to 1.9 per 100,000 population[3,4].CIDP has both motor and sensory symptoms, with motor being the predominant feature. There is symmetrical involvement of both arms and legs, including both proximal and distal muscles, resulting in global muscle weakness and a general reduction or absence of deep tendon reflexes[2]. Occasionally, muscl